Hi, I have problem with this LG model 55UB8500, it have no picture,I check voltage in Power Supply , all the voltages 24 volts 12 volts, 3.5 volts are there, when I push power ON, it have Red led on main board it stays red no blinking, on the power supply board when I put Power ON on connector P 802 LED + it have 48 volts on connector P 802 Led+ 48 volts, could you tell me what I have to check now?
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Re: LG 55UB8500 no picture.
Are backlights coming on, flashing? If not, is there a picture on screen using a flashlight?I assume no responsibility for any stupid suggestions I might post. -
Re: LG 55UB8500 no picture.
No picture with flashlight, no picture flashingComment
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Re: LG 55UB8500 no picture.
Someone?Comment
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Re: LG 55UB8500 no picture.
check fuse on tcon board, check for 12 volts on each side, neg. probe on metal chassis.Comment
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Re: LG 55UB8500 no picture.
I check it and no voltage on this fuse, I think Main Board is the problemComment
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Re: LG 55UB8500 no picture.
fuse has continuity, not blown?Comment
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Re: LG 55UB8500 no picture.
Yes continuity no voltage on itComment
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Re: LG 55UB8500 no picture.
need a good clear picture of the legend/map of the expected voltages of the connector on powerboard, can try stand alone test.Comment
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Re: LG 55UB8500 no picture.
here's a quick test, very carefully check the voltage of the big 460 volt caps on powerboard with tv powered on, careful to only touch it with the probes, 400 VOLTS is a lot of volts and can be deadly.Comment
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Re: LG 55UB8500 no picture.
I check and they have 400 volts, on my first post I told I have voltages on the plug who's goes on Main BoardComment
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Re: LG 55UB8500 no picture.
Check transistor that switches on voltage to t-con.I assume no responsibility for any stupid suggestions I might post.Comment
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Re: LG 55UB8500 no picture.
Do you have location number?Comment
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Re: LG 55UB8500 no picture.
Tv turning on with backlight but no picture, tcon board is first suspect. Connect one side at a time between tcon and panel to see if you get half an image. If you do, there is a panel short on the bad side and you can try the tape cutoff method. If no side displays an image, it is worth trying to replace the tcon.
OK, just noticed no voltage on fuse. Should have 12V with TV on. 12V is typically switched with a FET on the main board when you turn the TV on and passes through several pins of the LVDS connector.Last edited by neilc6; 07-29-2022, 11:14 AM.Comment
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Re: LG 55UB8500 no picture.
it have no backlight at firstComment
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Re: LG 55UB8500 no picture.
one of those, hey guys look into your magic 8 ball and tell me what's wrong with my tv. This is tv troubleshooting, tests need to be done promptly, as instructed and pictures can speed it up IMMENSELY, if I get a fighter I lose interest very quickly.Comment
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Re: LG 55UB8500 no picture.
That's photo of TCON , I don't have schematic of the tvAttached FilesComment
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Re: LG 55UB8500 no picture.
Why are you giving picture of t-con? You said you have no voltage going to t-con. Thus you need to look on main board and find where you are losing the 12v.I assume no responsibility for any stupid suggestions I might post.Comment
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Laptop is HP Envy x360 13-bf0013dx, hp website link, it's an i7-1250U with 8 gig onboard ram.
Platform: ipa32 la-m024p rev 1b
Originally you'd plug power supply into it and it would take up to 1.2 amps and then drop to 200 milliamps and then go back up again to 1.2, staying all the while at 5 volts. Pressing power button would results in power LED blinking amber 3 times. 3.3 volt rail, 5.1 volt rail present, main power rail 8.8 volts. Power button test pads near EC chip 2.7 volts.
I found a short on the other side:
...10-04-2025, 05:03 PM -
I saw this switching power supply on eBay and wanted to see if could be modified to run 14.5 volts before the blocking diode was add and this switching power supply seems to have no issues doing this
I did recap the switching power supply except the the main filtering capacitors and I managed to break the selector switch for the voltage setting but just jumped it
One note I used 25 volt capacitors on the output side of this power supply because they used 16 volt capacitors and because I am running the voltage up a little bit higher 12 volts to 14.5 volts there would... -
Hi everyone,
Sorry for the person who’s going to read all this !
I'm on a Nintendo Switch Lite, motherboard HDH-CPU-02.
While replacing the left joystick, I had to remove the motherboard to access the connector underneath. When I lifted the LCD connector latch, it broke (the plastic had become brittle over time), so I replaced the entire connector.
During the desoldering of the LCD connector using hot air, three small components located just below the connector (likely 0402 capacitors) came off and remained stuck to the bottom of the... -
Hi All,
Need help.
I have a samsung un60j620dafxza led tv. When I plug it in it has no display, no sounds, and no standby lights.
So I opened the tv and disconnected the power to the mainboard and the backlight powered up. This according to many people says that this is a mainboard
problem. I checked the voltage coming from the stb and I read 1.3 volts on pins 1,3,5 and 7 which are low volts instead of 13 volts which i think the lcd panel
might be drawing too much power from the power supply that it prevents the right voltage going to the mainboard....
Comment